Search results for "Geology"
showing 10 items of 6012 documents
HIGH-RESOLUTION SURFACE AND BED TOPOGRAPHY MAPPING OF RUSSELL GLACIER (SW GREENLAND) USING UAV AND GPR
2020
Abstract. This study presents the detailed survey of the northern marginal part of Russell Glacier, SW Greenland using the combination of unmanned aerial vehicle (UAV) photogrammetry and low-frequency ground penetrating radar (GPR) measurements. Obtained digital elevation model (DEM) and ice thickness data from GPR data allowed the generation of high precision subglacial topography model. We report uncertainties arising from GPR, GPS, and DEM suggesting sufficient accuracy for the reconstruction of glacier bed topography. GPR data and generated subglacial topography model does not reveal any possible Nye channel that could be incised into the bedrock, however, we were able to detect englaci…
TERRESTRIAL LASER SCANNING FOR COASTAL GEOMORPHOLOGIC RESEARCH IN WESTERN GREECE
2012
We used terrestrial laser scanning (TLS) for (i) accurate volume estimations of dislocated boulders moved by high-energy impacts and for (ii) monitoring of annual coastal changes. In this contribution, we present three selected sites in Western Greece that were surveyed during a time span of four years (2008-2011). The Riegl LMS-Z420i laser scanner was used in combination with a precise DGPS system (Topcon HiPer Pro). Each scan position and a further target were recorded for georeferencing and merging of the point clouds. For the annual detection of changes, reference points for the base station of the DGPS system were marked. Our studies show that TLS is capable to accurately estimate volu…
GEOMATIC TECHNIQUES FOR THE COLONNADE STRUCTURAL ANALYSIS OF THE HISTORICAL “CHIARAMONTE STERI” BUILDING
2019
Abstract. The monitoring of building structures has an increasingly important role in the engineering field, above all because they are concerned with the impact that such structures have in the area where they were built. Often, when walking through the old town centres, we realize just how obsolete and dangerous some buildings (even historic-cultural ones) are. The interest of some local governments in this problem has led, in the last few years, to the study and the trying out of measuring and monitoring methods which, quickly and at low cost, allow to define the extent of the deformation and the degrade in an accurate and reliable way.The Courtyard of “Palazzo Steri - Chiaramonte” is co…
ON THE FON ASTROPLATE PROJECT ACCOMPLISHMENT
2019
The plan of the photographic survey of thenorthern sky (FON) was proposed in 1976 in Golosiiv ob-servatory (now MAO NAS of Ukraine) by I. Kolchinskyand A. Onegina. The final project of the Compiled FONACcatalog (FON Astrographic Catalog) is based on the digitaldata of photographic plates exposed at four observatories.They are MAO NAS of Ukraine (Kyiv, Ukraine), Kitabastronomical observatory (Tashkent, Uzbekistan), Hissarastronomical observatory (Dushanbe, Tajikistan), and Bal-done observatory (Latvia)). The total amount of plates is5700. The result is expected to be the catalog of positionsand B-magnitudes of stars covered the declination areafrom -20 to 90 degrees. The estimated mean epoch…
Spatiotemporal hotspots analysis for exploring the evolution of diseases: An application to oto-laryngopharyngeal diseases
2013
Abstract View references (14) This paper presents a spatiotemporal analysis of hotspot areas based on the Extended Fuzzy C-Means method implemented in a geographic information system. This method has been adapted for detecting spatial areas with high concentrations of events and tested to study their temporal evolution. The data consist of georeferenced patterns corresponding to the residence of patients in the district of Naples (Italy) to whom a surgical intervention to the oto-laryngopharyngeal apparatus was carried out between the years 2008 and 2012
Vulnerability to climate change and adaptation strategies of local communities in Malawi: experiences of women fish-processing groups in the Lake Chi…
2016
Abstract. In recent years, research on climate change and human security has received much attention among policy makers and academia alike. Communities in the Global South that rely on an intact resource base and struggle with poverty, existing inequalities and historical injustices will especially be affected by predicted changes in temperature and precipitation. The objective of this article is to better understand under what conditions local communities can adapt to anticipated impacts of climate change. The empirical part of the paper answers the question as to what extent local women engaged in fish processing in the Chilwa Basin in Malawi have experienced climate change and how they …
Time evolution of medium and long-period ground tilting at Campi Flegrei caldera
2020
Abstract. We analyse tiltmeter time series recorded from April 2015 to March 2019 at three borehole instruments installed at Campi Flegrei caldera (Italy). We evaluate the crustal response in terms of ground tilting to external excitations of medium/long-period tidal constituents by applying a polarization analysis. The azimuths of the tilt vectors show well-defined polarization directions and the ground tilting planes oscillate with the periodicity of the corresponding tidal constituents. For two of the three tiltmeters, the average ground oscillation pattern related to the monthly Mm and fortnightly Mf constituents show seasonal variations, which can be ascribed to rainfall-induced tiltin…
Characterization of the seismic dynamical state through joint analysis of earthquakes and seismic noise: the example of Ischia Volcanic Island (Italy)
2020
This work is devoted to the study of both earthquakes and background seismic noise at Ischia Island (Italy) recorded pre and post the Md 4.0 earthquake occurred on 21 August 2017 (18:57 UTC). We compare and characterize noise and earthquakes in terms of Independent Component Analysis, energy and polarization properties. The earthquakes' waveforms and the background noise are decomposed into a few independent components with two main common signals peaked around 1–2 and 3–4 Hz, respectively. A slight increase of the energy of the background seismic noise is observed comparing samples recorded in 2016 and 2017, whereas no variations are detected in 2017 pre and post the main ear…
Morphodynamics of river bed variation with variable bedload step length
2013
Abstract. Here we consider the 1-D morphodynamics of an erodible bed subject to bedload transport. Fluvial bed elevation variation is typically modeled by the Exner equation, which, in its classical form, expresses mass conservation in terms of the divergence of the bedload sediment flux. An entrainment form of the Exner equation can be written as an alternative description of the same bedload processes, by introducing the notions of an entrainment rate into bedload and of a particle step length, and assuming a certain probability distribution for the step length. This entrainment form implies some degree of nonlocality, which is absent from the standard flux form, so that these two express…
A physical model for the interaction between unsaturated soils and retaining structures
2020
Temporary and permanent retaining structures interact with soils that are usually in unsaturated conditions. In this work, a 1g-scale physical model is presented to investigate the interactions between retaining walls and unsaturated soils. The physical model is equipped with a water-filled hydraulic cylinder connected to a pressure-volume controller to measure the horizontal component of the later earth thrust and high capacity tensiometers to measure soil matric suction. A system of low-friction linear guideways has been installed at the base of the wall-model. The failure surface is observed through a 3 cm thick glass wall on one side of the container. A series of images are acquired dur…